TestGL draft

WG,

As promised during Wednesday's talk with Patrick, Lofton and Dom, I've 
sent the document to Patrick for him to check.

Please note that I have limited the work to the following:

1. No proper layout since I want to gather all feedback and update the 
document before publication, thought I'd do the layout at the same time 
(this includes introductory/concluding sections)
2. I've tried to incorporate as much as possible of the old operational 
guidelines. Here I want to note that

(i) I think TestGL should not consist of that many operational 
guidelines (I realise there is a spillover from the old OpsGL, but I 
think they fit better in QAH)
(ii) I think QAH and TestGL editors need to commonly decide what gets 
put in QAH. Maybe we can do this before the next publication cycle.

Best,

/Dimitris